/*
 * Copyright (c) 2015 Spotify AB.
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package com.spotify.heroic.aggregation.simple;

import com.spotify.heroic.aggregation.Aggregation;
import com.spotify.heroic.aggregation.Empty;

import java.util.Optional;

/**
 * Utility methods for aggregations.
 */
public interface Aggregations {
    /**
     * Filtering aggregations should no longer permit a child aggregation.
     *
     * This is part of a fix for issue #79.
     */
    static void verifyNoChild(final String name, final Optional<Aggregation> aggregation) {
        aggregation.ifPresent(a -> {
            if (!(a instanceof Empty)) {
                throw new IllegalArgumentException(name +
                    ": filtering aggregations should not take a child aggregation any longer");
            }
        });
    }
}
